Buggy code:
public class TinyLeaders extends DeckValidator { protected List < String > banned = new ArrayList < > ( ) ; protected List < String > bannedCommander = new ArrayList < > ( ) ; public TinyLeaders ( ) { } public TinyLeaders ( String name ) { } @ Override public boolean validate ( Deck deck ) { boolean valid = true ; if ( ( deck . getCards ( ) . size ( ) ) != 49 ) { invalid . put ( "Deck" , ( ( "Must<seq2seq4repair_space>contain<seq2seq4repair_space>49<seq2seq4repair_space>cards:<seq2seq4repair_space>has<seq2seq4repair_space>" + ( deck . getCards ( ) . size ( ) ) ) + "<seq2seq4repair_space>cards" ) ) ; valid = false ; } List < String > basicLandNames = new ArrayList < > ( Arrays . asList ( "Forest" , "Island" , "Mountain" , "Swamp" , "Plains" , "Snow-Covered<seq2seq4repair_space>Forest" , "Snow-Covered<seq2seq4repair_space>Island" , "Snow-Covered<seq2seq4repair_space>Mountain" , "Snow-Covered<seq2seq4repair_space>Swamp" , "Snow-Covered<seq2seq4repair_space>Plains" ) ) ; Map < String , Integer > counts = new HashMap < > ( ) ; counts . put ( deck . getName ( ) , 1 ) ; countCards ( counts , deck . getCards ( ) ) ; countCards ( counts , deck . getSideboard ( ) ) ; for ( Map . Entry < String , Integer > entry : counts . entrySet ( ) ) { if ( ( entry . getValue ( ) ) > 1 ) { if ( ( ( ! ( basicLandNames . contains ( entry . getKey ( ) ) ) ) && ( ! ( entry . getKey ( ) . equals ( "Relentless<seq2seq4repair_space>Rats" ) ) ) ) && ( ! ( entry . getKey ( ) . equals ( "Shadowborn<seq2seq4repair_space>Apostle" ) ) ) ) { invalid . put ( entry . getKey ( ) , ( "Too<seq2seq4repair_space>many:<seq2seq4repair_space>" + ( entry . getValue ( ) ) ) ) ; valid = false ; } } } for ( String bannedCard : banned ) { if ( counts . containsKey ( bannedCard ) ) { invalid . put ( bannedCard , "Banned" ) ; valid = false ; } } if ( ( deck . getSideboard ( ) . size ( ) ) <= 10 ) { Card commander = GameTinyLeadersImpl . getCommanderCard ( deck . getName ( ) , null ) ; if ( ( commander == null ) || ( ( commander . getManaCost ( ) . convertedManaCost ( ) ) > 3 ) ) { if ( commander == null ) { <START_BUG> invalid . put ( "Leader" , "Please<seq2seq4repair_space>be<seq2seq4repair_space>sure<seq2seq4repair_space>to<seq2seq4repair_space>set<seq2seq4repair_space>your<seq2seq4repair_space>leader<seq2seq4repair_space>in<seq2seq4repair_space>the<seq2seq4repair_space>NAME<seq2seq4repair_space>field<seq2seq4repair_space>in<seq2seq4repair_space>the<seq2seq4repair_space>DECK<seq2seq4repair_space>EDITOR<seq2seq4repair_space>(use<seq2seq4repair_space>the<seq2seq4repair_space>names<seq2seq4repair_space>Mardu,<seq2seq4repair_space>Sultai<seq2seq4repair_space>or<seq2seq4repair_space>Jeskai<seq2seq4repair_space>as<seq2seq4repair_space>default<seq2seq4repair_space>Commanders)" ) ; <END_BUG> } if ( ( commander != null ) && ( ( commander . getManaCost ( ) . convertedManaCost ( ) ) > 3 ) ) { invalid . put ( "Leader" , "Commanders<seq2seq4repair_space>converted<seq2seq4repair_space>mana<seq2seq4repair_space>cost<seq2seq4repair_space>is<seq2seq4repair_space>greater<seq2seq4repair_space>than<seq2seq4repair_space>3" ) ; } return false ; } if ( ( ( commander . getCardType ( ) . contains ( CREATURE ) ) && ( commander . getSupertype ( ) . contains ( "Legendary" ) ) ) || ( ( commander . getCardType ( ) . contains ( PLANESWALKER ) ) && ( commander . getAbilities ( ) . contains ( CanBeYourCommanderAbility . getInstance ( ) ) ) ) ) { if ( ! ( bannedCommander . contains ( commander . getName ( ) ) ) ) { FilterMana color = CardUtil . getColorIdentity ( commander ) ; for ( Card card : deck . getCards ( ) ) { if ( ! ( cardHasValideColor ( color , card ) ) ) { invalid . put ( card . getName ( ) , ( ( "Invalid<seq2seq4repair_space>color<seq2seq4repair_space>(" + ( commander . getName ( ) ) ) + ")" ) ) ; valid = false ; } if ( ( card . getManaCost ( ) . convertedManaCost ( ) ) > 3 ) { invalid . put ( card . getName ( ) , ( ( "Invalid<seq2seq4repair_space>cost<seq2seq4repair_space>(" + ( card . getManaCost ( ) . convertedManaCost ( ) ) ) + ")" ) ) ; valid = false ; } } } else { invalid . put ( "Commander" , ( ( "Commander<seq2seq4repair_space>banned<seq2seq4repair_space>(" + ( commander . getName ( ) ) ) + ")" ) ) ; valid = false ; } } else { invalid . put ( "Commander" , ( ( "Commander<seq2seq4repair_space>invalide<seq2seq4repair_space>(" + ( commander . getName ( ) ) ) + ")" ) ) ; valid = false ; } } else { invalid . put ( "Commander" , "Sideboard<seq2seq4repair_space>must<seq2seq4repair_space>contain<seq2seq4repair_space>only<seq2seq4repair_space>a<seq2seq4repair_space>maximum<seq2seq4repair_space>of<seq2seq4repair_space>10<seq2seq4repair_space>sideboard<seq2seq4repair_space>cards<seq2seq4repair_space>(the<seq2seq4repair_space>Tiny<seq2seq4repair_space>Leader<seq2seq4repair_space>name<seq2seq4repair_space>must<seq2seq4repair_space>be<seq2seq4repair_space>written<seq2seq4repair_space>to<seq2seq4repair_space>the<seq2seq4repair_space>deck<seq2seq4repair_space>name)" ) ; valid = false ; } return valid ; } public boolean cardHasValideColor ( FilterMana commander , Card card ) { } }

Fix:
invalid . put ( "Leader" , "Please<seq2seq4repair_space>be<seq2seq4repair_space>sure<seq2seq4repair_space>to<seq2seq4repair_space>set<seq2seq4repair_space>your<seq2seq4repair_space>leader<seq2seq4repair_space>name<seq2seq4repair_space>in<seq2seq4repair_space>the<seq2seq4repair_space>NAME<seq2seq4repair_space>field<seq2seq4repair_space>in<seq2seq4repair_space>the<seq2seq4repair_space>DECK<seq2seq4repair_space>EDITOR<seq2seq4repair_space>(use<seq2seq4repair_space>the<seq2seq4repair_space>Sultai<seq2seq4repair_space>for<seq2seq4repair_space>a<seq2seq4repair_space>UBG<seq2seq4repair_space>(2//2)<seq2seq4repair_space>default<seq2seq4repair_space>Commander)" ) ;